Fuel injection device for internal combustion engines



H. ALFARO- 2,110,116

FUEL INJECTION DEVICE FOR INTERNAL COMBUSTION ENGINES March 1, 1938.

Filed Oct. 16, 1935 2 Sheets-Sheet l llv Illa/c.

INVENTOR Herae Zio Alf mo M? Ma an ATTORNEYS March 1, 1938. H. ALFARC 2,110,116

FUEL INJECTION DEVICE FOR INTERNAL COMBUSTION ENGINES Filed Oct. 16, 1935- 2 Sheets-Sheet 2 I INVENTOR Heraclio Alfaro 1-3 .12 BY .gqbma v ATTORNEYS Patented Mar. 1, 1? 38 STATES- PATENT OFFICE FUEL INJECTION DEVICE FOR INTERNAL COMBUSTION ENGINES 2 Claims.

The present invention appertains to the injection of fuel into the cylinders of internal combustion engines, and is particularly adaptable to cylinders having two pistons per cylinder operating on the two-stroke cycle principle with spark ignition.

My invention contemplates means whereby the fuel can be thoroughly mixed with the air charge in a cylinder without excessive dilution of the fuel with the lubricating oil on the interior wall of said cylinder.

The main objects of the invention are to obtain a very complete atomization of the fuel and a very thorough mixture of the fuel particles with 3 the air, to effect economy in fuel consumption,

and to make the firing of the fuel charges certain and dependable, and to obtain-these results without detrimental effect on lubrication.

Reference should be had to the accompanying drawings forming a part of this specification, in

V which:

Figure 1 is a sectional view showing a fuel injection device embodying the invention;

Fig. 2 is a sectional view showing a fuel injection device of somewhat diflerent construction also embodying the invention;

Fig. 3 is a sectional detail view showing the outlet of the injection nozzle in open position;

Fig. 4 is a sectional detail view showing the 0 spray forming tip' of the nozzle in side elevation; a

'Fig. 5 is a sectional detail view showing a deflector which may be used with the nozzle shown in Figs. 2, 3, and 4;

5 Fig. 6 is a diagrammatic view showing a complete cylinder, the injection nozzle, ignition devices and the streams or jets which may be discharged from the injection nozzle into the space between the pistons by a suitable arrangement .0 of the outlet openings of the nozzle shown in Fig.

Fig. 7 is a view similar to Fig. 6 showing the fuel streams or jets obtained by a different arrangement of outlet openings;

.5 Fig. 8 shows fuel streams or jets which may be obtained by another arrangement of outlet openings;

- Fig. 9 shows the fuel streams, or jets obtained by two oppositely disposed oblique discharge i0 Openings;

Fig. 10 is a view showing the fuel streams or jets obtained by the nozzle and deflector shown in Fig. 5;

Fig. 11- is a view showing oppositely disposed injection nozzles;

Fig. 12 is a sectional view showing a modification .of the invention in which the fuel injection nozzle is mounted in an air inlet port.

Heretofore it has been difficult to combine proper atomization of the fuel with low penetration and efficient mixing when the size of the cylinder is relatively small and the compression at the time of ,the injection is low. Moreover injection nozzles heretofore used have been expensive and bulky, or have required the installation of leak-01f lines. The present invention avoids these difliculties.

In Figs. 1 to 5 the construction of the fuel in.- jection nozzles embodying the invention are shown in detail, the arrangement of the nozzle with respect to the cylinder and pistons therein and with respect to the air intake and ignition devices being shown in diagrammatic views 6 to II inclusive.

Referring to Fig. 1 of the drawings, the injection nozzle indicated generally by the numeral l is mounted in an apertured threaded boss 2 of a cylinder 3 and has a body portion 4 provided with an axial bore 5 which terminates near the inner end of the body portion. The body portion I has a rounded tip 6 of reduced diameter which is provided with divergent openings 1 which provide outlets from the chamber formed by the bore 5 and which may be arranged in various ways to so direct streams of fuel into the cylinder as to effectively disperse the fuel in the air within the cylinder as will be hereinafter more fully explained.

The body portion 4 of the nozzle has a reduced cylindrical inner end portion 8 which fits within a sleeve 9 which fits within the aperture of the boss 2 and has a flange Ill adapted to seat upon the outer edge of the boss 2. The body portion 4 of the nozzle has a flange H which seats upon the flange ill of the sleeve 9 and is clamped to the cylinder by a sleeve nut 12 which screws upon the threaded boss 2. The sleeve 9 is preferably made of copper or other metal of high heat conductivity.

A fuel inlet nipple 13 provides means for admitting fluid fuel into the chamber formed by the bore 5. At the upper end of the body 4 the bore 5 is closed by an elastic wall [4 clamped upon the upper end of the body 4 by means of a screw cap l5. The elastic wall or diaphragm I4 is provided with circular corrugations l6 and is deformable by internal fluid pressure, the upper end of the body 4 being countersunk around the upper end of the bore 5 to provide an enlargement 11 in the pressure chamber beneath the elastic wall Ii. A valve stem I8 is rigidly attached to the center of wall it and extends. through the bore to adjacent the outlet and where it is provided with a conical faced valve member 19 which bears against a valve seat to cut ofi flow of fluid to the discharge tip 6. The valve member l9 isnormally heldfirmly seated by the elastic wall it to cut oif flow of fluid to the interior of the cylinder. Near the end of the piston stroke fluid fuel under pressure is delivered to the nozzle I by the usual mechanism timed with respect to the piston-movement. This fuel entering the bore 5 of the nozzle under high pressure acts upon the elastic wall Hi bending the wall outwardly and retracting the valve member 59 from its seat to permit fuel to flow from the nozzle chamber into the tip 6 and through the openings 1 into the cylinder. The valve member l9 preferably has a sliding fit in the bore 5 and is provided with grooves 20 to permit flow past the valve when the valve is shifted away from its seat. To prevent damage to the elastic wall l4 due to excessive deformation by internal pressure, means is provided to limit the deflection of the wall H. The wall of the cap i5 is closely adjacent the outer face of the elastic wall M and will permit the wall It to have only a very slight outward movement. In order to permit free escape of air from the so space between the cap l5 and elastic wall It the cap is provided with openings 2i.

In Figs. 2, 3, and 4 a modifiedform of injection nozzle is shown. This nozzle indicated generally by the numeral la has a body portion 22 provided with a threaded end adapted to screw into a threaded boss 23 in the cylinder wall.

- The body portion is bored to receive a cylindrical fuel conducting member 24 which has a reduced tapered elastic walled tip 25 which extends through a restricted opening at the inner end of the body 22. The opening at the inner end of'the body 22 is provided with a tapered seat 25. against which the tapered tip 25 bears .and against which the'tapered tip is pressed by means of a ring nut 21 which screws upon the threaded outer end of the body 2| and bears upon the outer face of a flange 28 on the member 24. The member 24 has an axial passage 29 for fluid fuel. The tip 25 is formed of two elastic wallforming members having fiat faces which abut in an axial plane and which are held firmly in contact by pressure against the tapered seat 26. The abutting faces are provided with grooves 30 which form a continuation of the passage 29 and have recesses 3| near their ends which provide an enlargement of the pressure chamber. The opening in the body 2| is enlarged between the seat 26 and the inner end of the body so that the ends 32 of the elastic walls of the tip are free to bend laterally when acted upon by the pressure of fluid in the chamber formed by the recesses M to separate the contacting walls at the end of the discharge tip and thus provide a narrow slit around the end and inwardly along the sides of the tip 25 through which a flatstream of fluid fuel-may flow into the interior of the cylinder. The body 2| is provided with stop shoulders 33 closely adjacent the opposite sides of the outer end of the tip 25 to limit the amount 2,110,118 formed faces which, insure fluid-tight contact.

The contacting faces of the tip halves and the contacting faces of the e nds of the tip halves 'tons 35 positioned at or near the outer ends of their strokes and spark plugs 35 positioned centrally of the cylinder and in circumferential alinement with the injection nozzle. Air inlet ports 31 are positioned near one'end of the cylinder so as to be uncovered by the piston at that end as the piston nears the outer, end of its stroke, and exhaust ports 38 are positioned near the opposite end of the cylinder, the injection of fuel and entry of air into the cylinder being timed to occur at or near the time when the pistons are in their outermost positions.

To obtain best results, the location of the nozale and the direction of the sprays of fuel are important. ,Whenused in combination with a double opposed piston cylinder, I have found it advantageous to place the nozzle of the type shown in Fig. 1 in the center of the cylinder which corresponds to the space where the combustion of the fuel actually -takes place.

If the operation of the engine is on the fuel injection spark ignition principle, I have found it advantageous to inject the fuel following the longest possible path and furnishing as much diffusion as possible with the air in the cylinder. This is better achieved when the two pistons are at or near the outer end of their stroke.

Figs. 6, 7, 8, 9/10, and 11 show various forms of sprays on this same principle, the main object being to inject from a point of the cylinder.

along the longest path and providing the greatest possible contact between the spray boundary and the air.

Fig. 6 for instance showsin perspective an arrangement that provides four jets or streams la directed obliquely across the cylinder towards the faces of pistons 35, the nozzle outlet in this instance being provided with pairs 'of openings at opposite sides thereof, each pair being disposed in a-plane extending obliquely across the cylinder axis and intersecting the face of a piston.

Fig. .7 shows four streams or jets lb .all disposed in a single plane with a pair of jets directed toward the face of each piston. 'In this instance two of the jets lb are directed toward the centers of the faces of the opposed pistons and the other two jets are directed across the cylinder at a greater angle to the cylinder axis.

Fig. 8 shows six jets 'Ic disposed in three planes, an arrangement which will provide better dispersion in large cylinders.

Fig. 9 shows two jets id such as provided by two openings 1 directed obliquely toward ppo-.

In some instances it may be desirable to provide a plurality of injection nozzles. Fig. 11 shows two nozzles arranged diametrically opposite each'other in the central portion of the cylinder.

Fig. 12 shows a modified construction in which a fuel injection nozzle indicated by the numeral lb may be mounted in an air inlet port 38 and provided with an outlet adapted to direct a jet indicated at 39a obliquely toward the opposite end of the cylinder at a relatively small angle to the axis of the cylinder.

It can be seen that I have provided advantageous means to inject the fuel in the cylinders of internal combustion engines of the type having two opposed pistons per cylinder. By providing an elastic walled chamber deformable by fluid pressure and opening the discharge outlet when so deformed,.leakage and the resulting need of leak-off pipes is avoided. By providing limiting stops for the elastic members, fatigue of the elastic elements is avoided. By directing the sprays along the longest paths in the cylinder and by properly distributing the sprays in the proper directions, a more perfect mixture of the fuel with the air is obtained, resulting in fuel economy and avoiding or reducing dilution of the oil film on the cylinder wall.

Furthermore, it is to be understood that the particular form of apparatus shown and described, and the particular procedure set forth, are presented for purposes of explanation and illustration and that various modifications of said apparatus and procedure can be made without departing from my invention as defined in the appended claims.

What I claim is:

1. In an internal combustion engine having two opposed pistons per cylinder, means for injecting fuel into said cylinder at times when the pistons are near the outer end of their stroke,

said injecting means including a nozzle in the wall of the cylinder at one side thereof substantially midway between its ends, said nozzle bein provided with means for directing divergent streams of fuel across the cylinder from the nozzle and toward the heads of the two pistons while the pistons are near the outer ends of their stroke;

2. In an internal combustion engine having two opposed pistons per cylinder, means placed in the wall of the cylinder at one side thereof substantiallymidway between its ends for inject- -ing fuel into said cylinder at times when the pistons are near the outer end of their stroke, and means for directing the fuel from said injecting means in divergent planes across the cylinder from said injecting means andtoward the heads of the two pistons while the pistons are near the outer ends of their stroke.

HERACLIO ALFARO. 

